1、Grammar： Modal verbs 情態(tài)動(dòng)詞,1,情態(tài)動(dòng)詞（modal verbs)： 表示說(shuō)話人的語(yǔ)氣或情態(tài)，如請(qǐng)求、命令、愿望、能力以及可能性等。英語(yǔ)的情態(tài)動(dòng)詞有：,2,can/could may/might must shall/should will/would need have to,能夠 可能 必須 應(yīng)該 意愿 敢 需要 不得不,+ 動(dòng)詞原形,3,4,一、情態(tài)意義表示法,1.表示“能力”和“可能” a)表示“能力”，可用can, could, be able to can既能表示現(xiàn)在的能力，也表示將來(lái)的能力。 Eg.Look! I can do it. I cant do

2、it now, but I can do it later.,5,現(xiàn)在“能力”：can, be able to As I have got enough money, I can/am able to help her. Can: 某樁具體事情：eg.I can climb this cliff. 泛指一般的“能力”： He can drive a car. She cant play the piano.,6,將來(lái)“能力”： 通常 will/shall be able to Ill be able to speak German in another two months 具體某事：can

3、Can you go and see him tomorrow morning? If I can, I will do it.,7,過(guò)去“能力”: could, was/were able to 肯定句： Could：一般能力 She could play the piano when she was only six. was/were able to(及managed to)：具體事件 He was able to translate the article without a dictionary.,8,I talked a long time, and in the end mana

4、ged to make her believe me. 在否定句中，could既可以表示過(guò)去一般能力，也可表示過(guò)去某具體事情的能力. I couldnt/wasnt able to play the piano when I was at school.,9,b)表示“可能”，可用may, might, can, could may/might： 既可以表示現(xiàn)在的可能，也可表示將來(lái)的可能，might在口氣上比may更委婉 現(xiàn)在：It may/might be true. 將來(lái)：He may/might leave tomorrow. 2.在疑問(wèn)句中，用can，不用may。 Can they h

5、ave missed the bus? Yes, they may have.,10,may not重音落在助動(dòng)詞上，表示“不可能”，重音落在否定詞上，表示“不許可” , 比較： He may not go tomorrow. He may not go tomorrow. 所以在書面語(yǔ)中，表示“不可能”常用cant,11,can/could表示現(xiàn)在的可能，口氣上could比較委婉 Thats not mine. Whose can it be? It could be Johns. can常用于否定句和疑問(wèn)句，而could不受此限。 If you dont have a guide, you

6、 could lose your way. It cant/couldnt be true. Can/could the news be true?,12,在肯定陳述句中，may與can的比較： Can指邏輯上的可能性，may指事實(shí)上的可能性 The road can be blocked.(按邏輯可能會(huì)堵，) The road may be blocked.(可能現(xiàn)在正堵著，事實(shí)上) Mr Reed is in poor health. He can be ill at any time. Mr Reed looks pale. He may be ill.,13,“may/might +h

7、ave done/have been doing”,“can/could +have done”表示過(guò)去的可能。 He may/might have missed the train. She may/might have been expressing her true feelings at that moment. She cant/couldnt have missed the train. “might/could +have done ”可以表示本來(lái)可能發(fā)生但沒(méi)有發(fā)生的，或者本來(lái)可能完成卻沒(méi)有完成的動(dòng)作， You might have finished the work last

8、week. I could have passed the examination, but I failed.,14,2表示“許可”和“不許” a)請(qǐng)求對(duì)方“許可”可用can, could, may, might. may/might較正式，could/might較委婉 表示給予“許可”通常用can/may,而不用could/might Could I use your phone? Yes, of course you can. Might I trouble you for a light? You may indeed.,15,b)表示“不許”可用may not或者cannot Can

9、 I go out for a moment? No, you cant. May I use your car for a few days? No, you may not. may not也可表示根據(jù)一般規(guī)定的“不許可”，而不是說(shuō)話人不許可 Borrowers may not take out of the library more than two books at a time. may not表示“不許可”的過(guò)去式不是might not He may not go.(=I dont permit him to go.) He might not go.(=Possibly he w

10、ill not go.) 過(guò)去的不許可：He was not allowed to go.,16,3表示“義務(wù)”和“必然” a)表示“義務(wù)”，可用should, ought to, must. 表示要求，命令時(shí)，語(yǔ)氣由ought to、 should、must漸強(qiáng) Should/ought to表示“應(yīng)該”，帶有敦促，勸說(shuō)之意，可交替使用，前者語(yǔ)氣更強(qiáng)。 You should/ought to drink less. Should/ought to +have done:本應(yīng)該 You should/ought to have asked my permission first. Must表示

11、敦促或命令，必須。 I really must stop smoking.,17,表示將來(lái)的“必須”，常用have to的一定形式（will/shall have to) 比較： We must do it again.(表示現(xiàn)在) Well have to do it again.(表示將來(lái)) 表示過(guò)去的“必須”，常用had to I had to leave at six yesterday. must有兩種否定形式:第一個(gè)是must not,表示“不許”、“禁止”,相應(yīng)的半助動(dòng)詞是be to的否定形式be not to You mustnt talk like that. You are

12、 not to talk like that.(不許你如此講話。),18,第二個(gè)否定形式是neednt,表示不必。 與neednt相當(dāng)?shù)膭?dòng)詞形式是dont need to/dont have to/havent got to A: Must you leave soon? B: No, I neednt/dont need to/dont have to/havent got to. 必須：must與have to must側(cè)重于說(shuō)話人的主觀意志 have to側(cè)重客觀需要 He must say it in English. (I want him to do so.) He have to

13、 say it in English. (He doesnt know Chinese.) 在特定語(yǔ)境中，用will也可表示“義務(wù)”，常用于第二人稱主語(yǔ)，這實(shí)際上是強(qiáng)化的祈使句。 You will wait outside the gate. Brian! You will close the door.,19,b)表示“必然”，可用should，ought to和must(一般用于陳述句)，其中must口氣最為肯定。都指說(shuō)話人根據(jù)一定情況做出推測(cè)或判斷. She should be here in a minute These young trees ought to provide sha

14、de in ten years . All men must die. ought to(表示“推測(cè)”）的否定形式是oughtnt to You oughtnt to have any difficulty getting the tickets.,20,如果是推測(cè)過(guò)去的事態(tài)，則用must +have done You must have left your handbag in the theatre. 表示推測(cè)的must的否定形式是cant不是must not If Fred didnt leave home before five, he cant be there yet.,21,4表

15、示“預(yù)見(jiàn)”和“推測(cè)” a)表示“預(yù)見(jiàn)”，即表示“單純將來(lái)”，可用will/shall+不定式，shall用于第一人稱，will用于第二、三人稱?，F(xiàn)在一般will可用于一切人稱表“將來(lái)” I will be a different person when I live in England. You will be hearing from me. She will probably last longer than you will. It will rain tomorrow. 非正式語(yǔ)體中，will常用語(yǔ)第一人稱主語(yǔ)表將來(lái)，常用will、shall的縮寫ll，模糊了其界限。 Ill com

16、e in after church and give you a hand.,22,b)表示“推測(cè)”，除用should, ought to,和must外，還可用will/would（語(yǔ)氣僅次于must）。 They should/ought to be home by now.(他們現(xiàn)在該到家了) They would be home by now.(他們現(xiàn)在大概到家了) They will be home by now.（我估計(jì)他們現(xiàn)在一定到家了） They must be home by now.（他們現(xiàn)在一定到家了）,23,will/would表示“推測(cè)”可有三種情況 1）對(duì)特定事態(tài)的推

17、測(cè) A: Whos that man over there? B: That will be George, no doubt. C: That would be George, I except. 2）對(duì)某些習(xí)慣性事態(tài)的推測(cè)，will指現(xiàn)在習(xí) 慣，would指過(guò)去習(xí)慣 He will work all day without a rest. Before his retirement he would catch the early bus every morning. 3）對(duì)某些不受時(shí)限的客觀過(guò)程的推測(cè)，只用will,表示現(xiàn)在時(shí)間，可與一般現(xiàn)在時(shí)的類似用法交替使用。 Pigs will e

18、at anything.=Pigs eat anything.,24,5表示“意愿”、“意圖”和“決心”， a)表示意愿都可用will, would, shall。 will用于一切人稱的主語(yǔ),可縮寫，will相當(dāng)于be willing to , I will lend you the money if you need it. My sister will help you with the luggage. You can help me if you will. Will用于第二，三人稱的疑問(wèn)句，是詢問(wèn)別人是否愿意做某事，請(qǐng)求 Will you please open the door

19、for me? 此時(shí)，will=would you, would you please, would you be good enough to ,would you like to, would you be so kind as to 表示接受請(qǐng)求時(shí)，用will不用would Would you lend me your pen a minute?Certainly, I will.,25,表示不愿意，用will not/wont I will not do anything solely for money. 表示過(guò)去的意愿或者不愿意用would, wouldnt,間接引語(yǔ) I aske

20、d him if he would help me with my writing. shall一般用于第二、三人稱主語(yǔ)，表示說(shuō)話人的意愿,而不是句子主語(yǔ)的意愿，在疑問(wèn)句中表示征詢聽(tīng)話人的意愿 You shall stay with us as long as you like=Im willing to let you stay with us as long as He shall be praised if he works hard for the people=Ill see that he is praised Shall you take a holiday this summe

21、r?,26,b)表示意圖，同上a)用法一致。 c)表示決心，同上 shall表示“決心”時(shí)，否定形式為shall not /shant，表示說(shuō)話人禁止、威脅 No one shall stop me.,27,6其他情態(tài)意義 should可在某些語(yǔ)境中表示惋惜、憂慮、歡欣、驚訝等感情色彩。例如在某些that-分句，慣用的疑問(wèn)句和感嘆句中。 How should I know? That he should dare to attack me! 還可用在某些語(yǔ)境中并不表示具體的情態(tài)意義。例如在be-型虛擬式中或狀語(yǔ)分句中。 I insisted that he go/should go with

22、me. They got warmly dressed for fear that they should catch cold. 此外，should還可以和say，think搭配表示婉轉(zhuǎn)口氣。 I should say he is just the right man for the job.,28,b) would可用于委婉的簡(jiǎn)述，客氣的請(qǐng)求,委婉的建議 I dont think he would be so careless.(委婉的陳述) Would you like to stay here for the night?(客氣的請(qǐng)求) Wouldnt it be better for

23、 us to start off a little earlier tomorrow morning？(委婉的建議),29,c)作為情態(tài)動(dòng)詞表示“膽敢”，dare通常只用于否定陳述句和疑問(wèn)句, I dare not go there. 多用于現(xiàn)在時(shí)形式，但它既可以指現(xiàn)在時(shí)間， The presidet was so hot-tempered that no one dare tell him the bad news. 也可指過(guò)去時(shí)間。否定形式為darent。 Tom wanted to come, but he darent. dare用作主動(dòng)詞，通常用于否定句和疑問(wèn)句。 He does n

24、ot dare (to) answer. dare的過(guò)去式dared通常只用于文學(xué)語(yǔ)言等正式語(yǔ)體，也還是用于否定意義。 Nobody dared lift their eyes from the ground.,30,d) need表示“必須，需要”，做情態(tài)助動(dòng)詞，只用于否定句和疑問(wèn)句， He neednt worry about it. 作情態(tài)助動(dòng)詞，答語(yǔ)肯定，must；否定，neednt Need we work late today? No, but we must tomorrow. Need I tell Elizabeth at once? No, you neednt tell

25、he just yet. 詢問(wèn)對(duì)方是否需要，必須做某事，可用need，也可用must, 否定用neednt或dont have to A: Must I see a doctor at once? B: No, you neednt/dont have to see a doctor for the time being.,31,Neednt +have done，表示過(guò)去本來(lái)不必做的事卻做了 You neednt have bought that house. Didnt need to 與neednt have +-ed比較： I didnt need to go to the stati

26、on.(因無(wú)必要不曾前往) I neednt have gone to the station.(本無(wú)必要卻在過(guò)去某時(shí)去了) e) used to(只有過(guò)去時(shí)形式，沒(méi)有現(xiàn)在時(shí)形式）表示過(guò)去習(xí)慣動(dòng)作或狀態(tài)，這種狀況已不復(fù)存在。 He used to live in Shanghai, usedt he? 在否定陳述句或否定疑問(wèn)句中，用didnt use to或usedt to均可。He didnt use to smoke cigarettes=He usednt to smoke cigarette. 在肯定疑問(wèn)句中有兩種形式： Used you to ?/Did you use to? Us

27、ed you to go to the same school as Edward?=Did you use to would表示“習(xí)慣”時(shí)，可與used to交替使用，區(qū)別在于would只與動(dòng)態(tài)動(dòng)詞連用，通常用于正式語(yǔ)體。,32,17.2 情態(tài)助動(dòng)詞的推測(cè)性用法和非推測(cè)性用法,33,uncertain might may could can should ought would will certain must,34,2能作推測(cè)性用法的情態(tài)助動(dòng)詞的句法特征 a)氣候的不定式可以采取完成體形式 You must have thought about it. b)其后的不定式可以采取進(jìn)行體形式

28、 He must be calling tonight c)可以用于there-存在句 There must be some mistake d)其后的不定式為一般形式（即非完成體或進(jìn)行體形式）時(shí)通常是靜態(tài)動(dòng)詞 He must be there e)主語(yǔ)可以是表示無(wú)生命物的名詞詞組 It must be George.,35,3能作推測(cè)性用法的情態(tài)動(dòng)詞與所指時(shí)間 1)直接引語(yǔ)中，說(shuō)話人的主觀看法總是以現(xiàn)在時(shí)間 為基點(diǎn)的。 2)說(shuō)話人所推測(cè)的事件所發(fā)生的時(shí)間，要根據(jù)不定式所采取的形式而定。 不定式若為非完成體形式則表示現(xiàn)在時(shí)間或?qū)?lái)時(shí)間；不定式若為完成體形式則表示過(guò)去時(shí)間。 He must be

29、 there.=Im sure he is there. He must have gone.=Im sure he has gone. went.,36,能夠(表能力),可以(表允許),必須,主語(yǔ) + can + 動(dòng)詞原形,主語(yǔ) + may + 動(dòng)詞原形,主語(yǔ) + must + 動(dòng)詞原形,主語(yǔ) + cannot/ cant + 動(dòng)詞原形,主語(yǔ) + may not + 動(dòng)詞原形,主語(yǔ) + must not/ mustnt + 動(dòng)詞原形,Can + 主語(yǔ) + 動(dòng)詞原形？,May + 主語(yǔ) + 動(dòng)詞原形？,Must + 主語(yǔ) + 動(dòng)詞原形？,Yes, 主語(yǔ) + can. No,主語(yǔ) + cant.

30、,Yes, 主語(yǔ) + may. No,主語(yǔ) + may not.,Yes, 主語(yǔ) + must. No,主語(yǔ) + neednt.,在口語(yǔ)中可用can代替，但may更禮貌。,37,1.My elder brother _(能) drive a car. 否定句： 一般疑問(wèn)句： 肯定回答： 否定回答： 就劃線部分提問(wèn)：,Practice,can,My elder brother cannot/cant drive a car.,Can your elder brother drive a car?,Yes, he can.,No, he cant.,What can your elder brot

31、her do?,38,2.You _ (可以) leave now. 否定句： 一般疑問(wèn)句： 肯定回答： 否定回答： 就劃線部分提問(wèn)：,Practice,may,You may not leave now.,May I leave now?,Yes, you may.,No, you may not.,When may I leave?,39,3.Lily _ (必須) go to the library. 否定句： 一般疑問(wèn)句： 肯定回答： 否定回答： 就劃線部分提問(wèn)：,Practice,must,Lily mustnt go to the library.,Must Lily go to

32、the library?,Yes, she must.,No, she neednt.,Where must Lily go?,40,A.用must(not), may(not), can(not)填空： 1.I dont understand this word. _ I use your dictionary? -Yes, please use it. 2.The traffic light is turning red. We _ stop. 3.You _ borrow two books at a time. 4.Tom _ play table tennis, but he _ play football. 5.Doctor, _ I take much medicine? -No, you neednt. But you _ drink a lot of water. 6.Tom is good at drawing. He _ draw wonderful pictures. 7.You _ smoke here. Its dangerous. 8.-May I turn on the TV? No, you _. My dad is sleeping.,Test You